Well tool utilizing a switch means responsive to both pressure and the wall area surrounding the switch



Dec. 31, 1968 J. a. SHORE 3,419,594

WELL TOOL UTILIZING A SWITCH MEANS RESPONSIVE TO BOTH PRESSURE AND TBE WALL AREA SURROUNDING THE SWITCH Filed Jan. 13, 1967 Sheet of 3 a W L J1 i' I I I mg q -/7 'e g l4 s A? J 1 i 32 f v k 30 2 Q! 44 I (fa/779a .5; Jfiore a INVENTOR.

ATTORNEY Dec. 31, 1968v J. a. SHORE 3,419,694 I WELL TOOL UTILIZING A SWITCH MEANS RESPONSIVE TO BOTH PRESSURE AND THE WALL AREA SURROUNDING THE SWITCH 1 Sheet 2 of 5 Filed Jan. 13, 1 967 (/'meJ 5. JAo/e INVENTOR ATTOR/VE) 3,419,694 TO BOTH PRESSURE SWITCH Sheet 5 J. B. SHORE ING A SWITCH MEANS RESPONSIVE HE WALL AREA SURROUNDING THE LIZ D T viz Dec. 31, 1968 WELL TOOL UTI AN Filed Jan. 13, 1967 /&me r .5. Jfiare INVENTOR. 13% Arra/wvfr United States Patent 3,419,694 WELL TOOL UTILIZING A SWITCH MEANS RE- SPONSIVE TO BOTH PRESSURE AND THE WALL AREA SURROUNDING THE SWITCH James B. Shore, Friendswood, Tex., assignor to Schlumberger Technology Corporation, Houston, Tex., a corporation of Texas Filed Jan. 13, 1967, Ser. No. 609,075 16 Claims. (Cl. 200-83) ABSTRACT OF THE DISCLOSURE A safety switch arrangement is provided for a string of tools to be pumped through the flow line of a well. The safety switch mechanism includes arm members which are released by hydrostatic pressure for outward extension. Upon positioning of the switch mechanism at a predetermined place in the flow line having a configuration allowing the switch arms to extend, a circuit is closed by such extension of the switch arms to actuate a tool in the string such as a perforating gun.

Background of the invention This invention relates to well tools, and more particularly, to well tool devices for being pumped through the flow line of a well.

It has been found advantageous in the completion of off-shore wells to place the well head assembly on the ocean floor rather than placing the assembly at the surface. Surface well heads have a disadvantage in that they constitute a navigation hazard for vessels operating in the water. Additionally, in deep water areas it may not be practical to erect a platform around the well head assembly at a point above the ocean floor due to the depth at which the platform must be anchored.

A system has been developed which utilizes a central gathering station having several wells spaced therefrom and flow lines connecting the central gathering station with the well head assembly located on the floor of the body of Water. These flow lines, which may be of considerable length, run horizontally along the ocean floor to the well head assembly at which point a radius is formed in the flow line at the well head assembly to permit the passage of a flexible string of tools through the flow line around the radius and into the well tubing string. Therefore, instead of using conventional floating rigs forservice jobs to be performed on the wells, a method is performed whereby well service tools are pumped through the flow line from the central gathering platform. This movement of tools through the flow line is accomplished by applying fluid pressure behind the tools to pump them into position in the well. Well tool strings utilized in such a system must be of such flexibility as to be capable of being pumped through the flow line around the radius in the flow line and into the tubing string. Virtually all tools presently run into Wells on a wire line may be adapted to such a system; including perforating, logging, cementing, and various other maintenance or work-over tools.

Since no mechanical connection is maintained with these tools which are pumped through the flow line," it is extremely important that the position of the tools in the tubing be known so that the work may be performed at the desired depth. Additionally, it is preferable that'tools which normally contain explosive charges, such as perforating devices, not be capable of being fired until they have been positioned at the desired depth in the well. It is also desirable that such tools be disarmed when returned to the surface in case of malfunction.

It is, therefore, an object of the present invention to Patented Dec. 31, 1968 "ice provide new and improved apparatus for safely positioning and conditioning a device for operation in the flow line of a well.

Summary of the invention With this and other objects in view, the present invention contemplates a string of tools arranged for pumping through a flow line into a well to perform an operation in the well such as perforating. Switching devices are included in the tool string which upon positioning at a predetermined location relative to the flow line are actuated to close electrical circuits in the string of tools and thereby operate a well tool. The switching devices utilize arm members which are released by hydrostatic pressure in the flow line to move outwardly relative to the tool string into engagement with the flow line or into void spaces in or beneath the flow line. Movement of the arms to a predetermined position causes mechanical linkages within the devices to actuate switches in the tool string and thereby close electrical circuits to the tool being operated.

A complete understanding of this invention may be had by reference to the following detailed description when read in conjunction with the accompanying drawings illustrating an embodiment thereof, wherein:

Brief description of the drawings FIGURE 1 shows a well head having flow tubes extending into a well bore and a string of tools positioned in the flow tube;

FIGURES 2A and 2B are longitudinal views partially in cross section of a string of tools for perforating a well;

FIGURE 3 is a longitudinal sectional view of a switch device;

FIGURE 4 is a longitudinal sectional view of the switch device with portions in side elevation;

FIGURE 5 is a cross-sectional view taken along lines 55 of FIGURE 3;

FIGURE 6 is a cross-sectional view taken along lines 66 of FIGURE 3; and

FIGURE 7 is a longitudinal sectional view of an alternative embodiment of a switch device.

Description of the preferred embodiments Referring now to FIGURE 1, a string of tools is shown positioned in a well bore 11 for perforating a well by use of through the flow line techniques. A pair of parallel flow lines 12 and 13 are shown entering a well head 15 and'extendin-g downwardly into the well bore. A packer device 17 isolates a portion of the well bore. A landing seat 19 is provided in the lower end of one of the flow lines to arrest downward travel of well tools therein. Such through the flow line apparatus and techniques are described in greater detail in copending application Ser. No. 389,389, now Patent No. 3,378,069.

The string of tools shown in FIGURES 1, 2A and 2B are made up of several sections. The upper section 14 is a transport head having seal means 16 thereon to provide a seal between the tool and the interior of the flow line and thereby facilitate pumping of the tool string through the flow line. A connecting link 18 connects the transport head with another section 20 which carries a power source or batteries 22. A seating shoulder 24 is formed on the section 20 and provides a means for locating the tool in the lower end of the flow tube, the seating shoulder 24 being engageable with the inwardly extending shoulder 19 at the lower end of the flow tube 13 to impede further travel of the tool string therethrough. Section 20 is connected by means of another connecting link 18 to a first switch section 26. Switch section 26 has flow tube engaging arms 28 for pivotally extending therefrom to follow the interior wall of the flow tube. At a known position relative to the end of the flow tube, the arms are effective upon extension of a preselected amount, to close an electrical circuit within the string of tools.

Switch 26 is connected by means of a connecting link 18 to a second switch section 30 which is similar in operation to switch section 26. Switch section 30 is connected by means of a connecting link 18 to a switch section 32. A pressure sensitive switch 33 is positioned within section 32 for closing the electrical circuit in the string of tools. A pressure senitive diaphragm 35 is positioned above switch 33 to operate the switch upon subjection of the device to a predetermined hydrostatic pressure. Another link 18 connects the pressure sensitive switch housing 32 with an eccentralizer section having a wall-engaging member 36 extending therefrom. The member 36 is spring biased to push outwardly against the wall of the casing. A perforating gun 38 is connected to the lower end of the eccentralizer section. The perforating gun has shaped charges 40 positioned therein and detonating means 42, including a detonating cord and electric blasting cap, for connecting the charges with the electrical circuit in the string of tools. The perforating gun is provided with a housing 44 formed of one or more relatively thin strips of metal which are flexible enough to permit travel through the flow line. Other means, of course, may be utilized to render the gun flexible for pumping through a flow line. The eccentralizer maintains the perforating gun eccentered in the casing so that the maximum clearance between the shaped charges and the casing wall is approximately one inch.

Referring now to FIGURE 3 of the drawings, the switch mechanism which is housed in sections 26 and 30 is shown in greater detail. Each switch section has a housing 46 with a pair of articulated arms 28 extending therefrom. (Only one pair of arms is fully shown.) Each pair of arms is comprised of upper and lower segments 48, 50, respectively, which are pivotally attached to the housing at 49 and 51, respectively. Adjacent end portions of the arms are coupled to one another by means of a pin 52 and slot 54 to permit sliding relative movement between the arm segments. The upper arm segment has an L-shaped portion 56 which extends inwandly toward the center of the switch housing. Elongated slots 58 are provided on opposite sides of the switch housing to permit the arms 28 to be received within the housing and thereby facilitate contraction of the arm segments.

Upper and lower cavities 60, 62 are provided at each end of the housing. The cavities are shaped to receive latching means on mating tool sections to permit coupling of the switch sections to adjacent tool sections. The lower end of the housing has a threaded detachable portion 61 which includes the portion forming the cavity 62. Portion 61 is removable to permit assembly of an O-ring retainer 64 and O-ring 66 within the interior of the housing to seal off a switch chamber 68 in the lower end of the housing.

A stepped bore 82 extends through the switch housing 46. A pusher or mandrel 74 is movably received in the upper half of bore 82. A flange 75 is formed on the pusher 74 midway between its ends. A bore 76 is formed axially within the pusher 74 to slidably receive the upper end 78 of a push rod 80. A spring 83 is connected between the upper end 78 of the push rod and a spring retainer pin 84 which is received in the slotted upper end of the pusher 74. The L-shaped portion 56 of the upper arm segment 48 is connected by means of a slot to a pin 72 in the upper end of the pusher 74.

A collet 86 is positioned midway in the bore 82 with spring arms 88 extending downwardly into a smaller diameter portion of bore 82. The spring arms 88 have inwardly projecting retainer segments 90 at their lower ends. The shoulder on the pusher 74 engages the collet 86 when the arms 28 are fully extended as shown in FIGURE 3. When the switch section is in the going-in position as shown in FIGURE 4, the retainer segments on spring arms 88 are held inwardly beneath the lower end of the pusher 74 by means of a push-rod cup 92 which is mounted on the push rod 80. The lower end of the push rod 80 extends through an O-ring retainer 94 and stufling box 96 which receives O-rings for sealing off the lower half of the housing, including the switch chamber 68, at atmospheric pressure. A spring follower 98 is threadedly connected to the lower end of the push rod. The spring follower has a central bore slidably received about the lower end of stufliing box 96. An outwardly extending flange 100 on the upper end of follower 98 engages the upper end of a spring 102. The lower end of the spring 102 is seated against flange 103 in the lower end of bore 82. The stufling box 96 is held in position within the bore '82 by means of a shoulder 105 formed therein and a retainer pin 97 engaging a beveled upper end of the stufling box.

Referring next to FIGURE 5, a cross section of the housing 46 is shown with the pusher 74 positioned therein. The shoulder 75 of the pusher is connected by arm 106 to the upper end of a switch actuating rod 104. FIGURE 4, in the partial elevational view, shows the switch actuating rod 104 extending longitudinally along the switch housing 46. A bore 107 is formed in the housing near the upper end of rod 104 for receiving the upper end of a spiraled spring. The spring 108 provides alignment to the rod and support to the upper end of the rod during movement thereof. The lower end of the rod 104 is connected to a switch actuating lever 109. The rod 104 is divided into upper and lower portions which are threadedly connected at 112 to permit adjustment of the length of the rod and thereby control the switch actuating dimensions of the articulated arms 28.

FIGURE 6, taken along lines 6-6 of FIGURE 3, shows the switch actuating mechanism in cross section. A micro switch 113 (see also FIGURE 3) is positioned within the switch chamber 68. The lever 109 which is pivotally attached to the lower end of the rod 104 has its opposite end connected to a shaft 114, which shaft is mounted for rotation within the housing. A contact arm 116 extends perpendicularly from the shaft 114 and is positioned above a micro switch contact pin 117. Longitudinal passages 118 in the housing provide means for passing electrical conductors through the housing.

In the operation of the above-described apparatus, the string of tools is assembled at the surface or on the gathering platform (not shown) and inserted into flow line 13. Special launching tubes, of a larger diameter than the flow line, may be provided at the surface to facilitate insertion of the tool string into the flow line. Pressure is then applied to the flow line behind the tool string to force or pump the string of tools through the flow line into the well bore as shown in FIGURE 1. Upon reaching the bottom of the flow line, the tool string is seated at the lower end of the flow line. Connecting links and flexible extension members (not shown) may be included in the string of tools where needed to provide for the proper positioning of a perforating gun below the end of the landing nipple in the flow line. As the switch devices 26, 30 drop below the end of the flow tube into the well bore, suflicient clearance is provided about the switch devices to permit extension of the arm members 28 outwardly from the switch housings.

Referring now to FIGURE 4 of the drawings, the switch apparatus is shown as it is arranged in the goingin position, that is, with the arm members contracted within the switch housing. After reaching a certain depth in the flow line, hydrostatic pressure in the well bore acting on the upper end of push rod 80 causes the push rod to move downwardly within the interior bore of the housing. The other end of the push rod is acted upon by atmospheric pressure, therefore, the hydrostatic pressure of the well bore forces the rod downwardly, such movement only being impeded by the action of the spring 102 which pushes upwardly on the push rod through the spring follower 98. The spring force, however, is

designed so that hydrostatic pressures at perforating depths will overcome the resistance of the spring to move the push rod downwardly. Such downward movement of the push rod also moves the attached push-rod cup 92 downwardly. Downward movement of the push-rod cup uncovers the spring arms 88 which are biased outwardly when in the position shown in FIGURE 4. Such outward movement of the spring arms moves the retainer segments 90 from beneath the lower end of the pusher 74. Thereafter, the spring 83 which is positioned in the axial bore 76 of the pusher exerts a downward pull on the pusher mechanism. Thereafter, when the switch device exits from the lower end of the flow tube, the pusher moves downwardly within the bore 82 of the switch housing. Such downward movement of the pusher mechanism is transmitted via the L-shaped portion 56 to the upper arm 48 to cause the arm members 28 to pivot outwardly about pivot points 49 and 51. Thereafter, the force of spring 83 holds the arms extended outwardly. Such outward movement of the arms, at least to the extent shown in FIGURE .3, is permitted only when the switch mechanism has been positioned at a place in the flow tube or beneath the flow tube which will not restrict such full extension.

Upon such outward movement of the arms 28 and downward movement of the pusher 74 within the switch housing, the flange 75 on the pusher 74 transmits this downward motion to the actuating rod 104 (FIGURE 4) extending along the outside of the switch housing. Downward movement of the actuating rod 104 in turn causes the lever 109 to pivot which in turn causes the shaft 114 (FIGURE 6) to rotate about its axis. Rotation of shaft 114 moves the contact arm 116 downwardly into contact with contact pin 117 on micro switch 113. Such depression of the contact pin closes a circuit within the micro switch which, in turn, is positioned within a firing circuit extending through the tool string.

As shown in FIGURE 1, both of the switch housings 26 and 30 must extend below the flow tube before the arms are permitted to extend outwardly and close the circuit switches within the housings. In addition, the pressure switch 33 is actuated at some point during the movement of the tool string through the flow tube when the hydrostatic pressure within the string is sufliciently high to move the diaphragm 35 downwardly against the switch 33 to actuate the switch and thereby close the firing circuit within the string of tools.

Upon closing of the three switches within the tool string, energy supplied by batteries 22 in the housing 20 is connected by means of the firing circuit to the detonating means 42 in the perforating gun 38 at the lower end of the tool string. Thereafter, detonation of the perforators is affected to perforate the casing in the well.

After perforating the well, pressure is released from flow line 14 and applied to flow line 12 which in turn places pressure on the lower end of upper section 14. This reverse pressure on the upper section lifts the tool string upwardly in flow line 13 to return the string of tools to the surface. As the switch devices 26 and 30 reenter the fiow line, the arms 28 are cammed inwardly by the pumping force on the string of tools. As the tool string moves upwardly in the flow line, hydrostatic pressure on the switch devices decreases. Upon such reduction in pressure, spring 102 forces push rod 80 and cup 92 to move upwardly against spring arms 88 (see FIGURE 3). This in turn applies an upward force to shoulder 75 on the slider which forces the arms 28 to move into their contracted position. Therefore, if the perforating gun has malfunctioned or otherwise failed to operate, the mechanism just described will disarm the system so that upon reception of the tools into the launching tube or removal of the tools from the flow line, the arms will not extend to close the firing circuit.

An alternative embodiment of a switch mechanism is shown in FIGURE 7 wherein a pair of switches and switch actuating devices are shown enclosed in a single housing. The housing 120 is shown having a central section or chamber 122 which is sealed at its upper and lower ends by means of plugs 124 and 126, respectively. The chamber 122 is maintained at atmospheric pressure by O-ring seals on the plugs. The upper end of the housing has a pair of articulated arms 128, pivotally connected to the housing at pivot points 132, 134, respectively. Inwardly extending end portions of the arms are pivotally connected at 136 to a switch actuating rod 138 which is centrally and slidably received within an upward extension 127 of the plug 126. A spring 140 is positioned between the extension 127 and a shoulder 142 on the rod 138. Spring 140 urges the rod toward the upper end of the tool and thus urges the arms inwardly into a collapsed position as shown in FIGURE 5. The opposite end of the rod 138 has a notched portion 139 which normally engages a lever 141 of a micro switch 143 to maintain the lever in an open circuit position. Upon movement of the rod downwardly, the end of the micro switch lever 141 cams out of the notched portion of the rod and onto the larger radius of the rod to depress the lever 141 and thereby actuate the micro switch 143. Movement of the rod 138 downwardly against the spring 140 is caused by fluid pressure in the form of a hydrostatic head acting upon the upper end of rod 138 against atmospheric pressure acting on the other end of rod 138 in chamber 122.

At the lower end of the housing 120, another pair of articulated arms 144, 146 are connected to the housing at pivot points 151, 153, respectively. Each of the arms 144, 146 is pivotally connected to an actuating rod 150 at pivot point 155. Actuating rod 150 is slidably received through an axial bore in the plug 124. A spring 152 is positioned between the plug 124 and a flange 154 on the rod to normally urge the rod downwardly. Such downward positioning of the rod causes the arms 144, 146 to pivot inwardly into the collapsed position as shown by the full lines in FIGURE 7. As with the switch mechanism at the opposite end of the housing, hydrostatic pressure acting on the lower end of rod 150 will move the rod upwardly against the force of spring 152 and atmospheric pressure in chamber 122 to actuate a micro switch 156 in chamber 122. Micro switches 143, 156 are series connected in a circuit within a string of well tools. Upon proper positioning of the switch housing in a flow line or the like, the upper and lower pairs of arms are simultaneously positioned in a predetermined configuration of the flow line to actuate the switches and complete a circuit in the string of tools to operate a well tool such as a perforating gun. It is readily seen that both pairs of arms may be set to actuate the switches upon expansion of the arms as they pass from the lower end of the flow line. However, one or both sets of arms may be arranged to actuate a switch upon expansion within a nipple within the flow line which provides an enlarged diameter of the flow line. For example, the switch mechanism of FIGURE 7 may actuate the upper micro switch upon expansion of arms 128, 130 within a nipple and actuate the lower switch upon emergence of arms 144, 146 from the lower end of the flow line. Such a system, of course, would require precise prepositioning of nipples within the flow line before installing the flow line.

As the switch device of FIGURE 7 is returned to the surface, the reduction in hydrostatic pressure permits the springs 140 and 152 to force the arm members to their normally retracted positions. This, in turn, insures that the perforating gun is disarmed when the tool string reaches the surface.

While particular embodiments of the present invention have been shown and described, it is apparent that changes and modifications may be made without departing from this invention in its broader aspects and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.

What is claimed is:

1. In a perforating gun for perforating earth formations traversed by a well conduit, a firing circuit including an electrical power supply and switch means, said switch means having pressure means responsive to pressure in a well and diameter sensing means responsive to the size of a well conduit for actuating said gun device when said device is in a well conduit.

2. The apparatus of claim 1 and further including a second switch means in said electrical firing circuit and operable solely in response to pressure within the well.

3. In a string of well tools for being pumped through the flow line of a well, a transport device in said string of tools and having seal means thereon to facilitate pumping of said tool string through a flow line, an electrical circuit in said string of tools for supplying electrical energy to an electrically operated device, and at least one switch mechanism for activating said electrical circuit, said switch mechanism having a circuit closing means operable in response to both pressure in the well and the dimension of the area surrounding the switch mechanism.

4. The apparatus of claim 3 and further including a power supply means in said string of tools for providing electrical energy to operate said electrically operated device.

5. The apparatus of claim 3 wherein said electrically operated device is a perforating gun and further including means on said string of tools for locating said perforating gun relative to the lower end of the well flow line.

6. A switch apparatus for operating a well tool comprising: a housing, arm means movably mounted on said housing for expansion and contraction relative to said housing, means normally maintaining said arm means in a contracted position, means responsive to fluid pressure for releasing said arm means for outward movement, means for moving said arm. means outwardly relative to said housing, electrical circuit means in said housing, switch means in said electrical circuit means, and means responsive to the movement of said arm means a predetermined distance for operating said switch means.

7. The apparatus of claim 6 wherein means are provided for urging said arm means to a retracted position after operation of said releasing means and in response to a decrease in fluid pressure.

8. The apparatus of claim 6 wherein said moving means includes spring means for urging said arm means to move upon operation of said releasing means.

9. In a well tool for use in a well bore, a switch apparatus including: a housing, arm means pivotally attached to said housing for movement between expanded and contracted positions, a chamber in said housing and having a pressure therein which is substantially less than the pressure normally encountered in a well bore, a movable member having an end thereof extending through a wall of said chamber, seal means providing a pressure sealed sliding engagement between said movable member and the wall of said chamber, arm means attached to said movable member, said arm means being expandable relative to said housing upon movement of said movable member in one direction, and switch means in said housing, said switch means being operable upon movement of said movable member.

10. The apparatus of claim 9 and further including means for resisting the movement of said movable member.

11. The apparatus of claim 9 and further including resilient means for transmitting the motion of said movable member to said arm means.

12. The apparatus of claim 9 and further including means for releasably holding said arm means from movement, said holding means being responsive to a predetermined pressure in the well bore to release said arm means for movement.

13. In a switch apparatus for pumping through the flow line of a well, a housing, a chamber at atmospheric pressure within said housing, a pair of movable members extending into said chamber through opposite walls of said chamber, seal means for providing a sealed sliding engagement between said movable members and said chamber walls, arm means connected to said movable members and mounted on said housing for movement between expanded and contracted positions, switch means in said housing, said switch means being operable in response to a selected amount of movement of said movable members.

14. The apparatus of claim 13 and further including means for providing a resisting force to the movement of said movable members.

15. In a perforating gun for perforating earth formations traversed by a well conduit, a firing circuit including an electrical power supply and switch means, said switch means including arm members extendible in said well conduit for electrically connecting said firing circuit to said power supply, and means for fully retracting said arm means upon retrieval of said perforating gun to the surface to open the circuit to said power supply.

16. The apparatus of claim 15 wherein said arm members are extendible by the force of hydrostatic pressure in the well bore.

References Cited UNITED STATES PATENTS 2,029,490 2/1946 Lane 20083 X 2,275,473 3/1942 Scaramucci 20()83 X 2,615,080 10/1952 Mathews et al. 2,657,576 11/1953 Boykin 34018 X 3,043,225 7/1962 Nielsen ZOO-83.91 X

ROBERT K. SCHAEFER, Primary Examiner,

H. BURKS, Assistant Examiner.

U.S. Cl. X.R. 

